1. Case Study: Students to read an article ‘Eyes without a Face – Stem cell research and corneal implants’, and prepare a group consultation (5-6 students per group) involving discussion of the following topics and the possible conclusion to the case: a. Stem cell function: differentiate adult and embryonic b. Corneal-limbus stem cells — their function and use in transplants c. Amniotic membrane use in cornea transplantation d. Cornea transplant success and failure e. Concerns with stem cell use in cornea transplants 2. Students will conduct online research to find out the possible outcome of the case study. Groups are to post their findings and conclusion in the Health Science blog & each student is to reflect the learning point from the other group
Tuesday, January 26, 2010
Eyes Without a Face: Stem Cell Research
Posted by SST Health Science 104 at 1:38 PM
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5 comments:
a) embryonic and adult stem cells may differ in the likelihood of being rejected after transplantation
Adult stem cells, and tissues derived from them, are currently believed less likely to initiate rejection after transplantation. This is because a patient's own cells could be expanded in culture, coaxed into assuming a specific cell type
Embryonic stem cells can be grown relatively easily in culture. Adult stem cells are rare in mature tissues, so isolating these cells from an adult tissue is challenging
Source: http://stemcells.nih.gov/info/basics/basics5.asp
b) Limbal stem cells are used in transplants as when a transplant is successful, a new healthy layer of cells will be produced in the patient’s eye. The success rate varies from 25 percent to 70 percent, depending on the underlying condition of
the affected eye.
http://www.isscr.org/public/eye.htm
c)It replaces the scarred cornea with the cornea of the donor cornea. This method is widely used to cure eye diseases and infections.
http://www.tectc.sg/cornea.html?gclid=CPr5rK_CwZ8CFcgtpAod-gwU0w
d) The patients that gone through cornea transplant has an 80% survival rate 10 years after the surgery. If the surgery fails, the patient might get ocular surface disease. Examples are infections and ulcer. Lucky, there are medications to treat the ocular surface disease. There is also a posibility that the patient will reject the cornea. If the surgery is a success, the patient will be able to see again.
source; http://www.cornea.org/study_database.html
e)risks is bleeding, infection of eye, swelling of the front of the eye, high pressure in the eye that can cause vision loss.
source:http://www.umm.edu/ency/article/003008ris.htm
younger people have a higher rate of graft rejection
http://emedicine.medscape.com/article/1193505-overview
there are many risks so people may not want to have a corneal transplant, no matter how low the percentages are.(personal opinion)
Conclusion: Lucy's sight was restored and although there were some difficulty adjusting at first, she soon adapted and she lived happily ever after! (like snow white, cinderella, and all the other fairytale stories)
junhui, fatin, helene, wei kang, isaac
a) embryonic and adult stem cells may differ in the likelihood of being rejected after transplantation
Adult stem cells, and tissues derived from them, are currently believed less likely to initiate rejection after transplantation. This is because a patient's own cells could be expanded in culture, coaxed into assuming a specific cell type
Embryonic stem cells can be grown relatively easily in culture. Adult stem cells are rare in mature tissues, so isolating these cells from an adult tissue is challenging
Source: http://stemcells.nih.gov/info/basics/basics5.asp
b) Limbal stem cells are used in transplants as when a transplant is successful, a new healthy layer of cells will be produced in the patient’s eye. The success rate varies from 25 percent to 70 percent, depending on the underlying condition of
the affected eye.
http://www.isscr.org/public/eye.htm
c)It replaces the scarred cornea with the cornea of the donor cornea. This method is widely used to cure eye diseases and infections.
http://www.tectc.sg/cornea.html?gclid=CPr5rK_CwZ8CFcgtpAod-gwU0w
d) The patients that gone through cornea transplant has an 80% survival rate 10 years after the surgery. If the surgery fails, the patient might get ocular surface disease. Examples are infections and ulcer. Lucky, there are medications to treat the ocular surface disease. There is also a posibility that the patient will reject the cornea. If the surgery is a success, the patient will be able to see again.
source; http://www.cornea.org/study_database.html
e)risks is bleeding, infection of eye, swelling of the front of the eye, high pressure in the eye that can cause vision loss.
source:http://www.umm.edu/ency/article/003008ris.htm
younger people have a higher rate of graft rejection
http://emedicine.medscape.com/article/1193505-overview
there are many risks so people may not want to have a corneal transplant, no matter how low the percentages are.(personal opinion)
Conclusion: Lucy's sight was restored and although there were some difficulty adjusting at first, she soon adapted and she lived happily ever after! (like snow white, cinderella, and all the other fairytale stories)
junhui, fatin, helene, wei kang, isaac
a. One major difference between adult and embryonic stem cells is their different abilities in the number and type of differentiated cell types they can become. Embryonic stem cells can become all cell types of the body because they are pluripotent. Adult stem cells are thought to be limited to differentiating into different cell types of their tissue of origin.
Source: http://stemcells.nih.gov/info/basics/basics5.asp
b. -To reconstruct the cornea (eg, replacing a perforated cornea)
-To improve the optical qualities of the cornea and thus improve vision (eg, replacing a cornea that is scarred after a corneal ulcer, is clouded because of edema as occurs in Fuchs' dystrophy or after cataract surgery, is opaque due to deposits of nontransparent abnormal corneal stromal proteins as occurs in hereditary corneal stromal dystrophy, or has irregular astigmatism as occurs with keratoconus)
Source: http://www.merck.com/mmpe/sec09/ch102/ch102m.html
c. Amniotic membrane has been used to treat burns and can be used for corneal transplant since it can promote the growth of cornea tissue.
d. The cornea seems to be very successful with an overall first year survival rate as high as 90%. Unfortunately, the long term reality is that the overall success rate goes down to 74% at 5 years and 62% at 10 years. In those eyes considered to be “high risk”, especially those with corneal diseases like neovascularisation or ongoing ocular inflammation, the long term 10 year survival rate is less than 35%. What is really scary is that these survival rates have not improved over the past 10 years.
Source: http://bjo.bmj.com/content/84/8/813.extract
e. A common concern would be that the stem cells may replicate uncontrollably and not properly differentiate. But most corneal transplants have been successful.
Source: http://www.cordbloodbankupdates.com
Conclusion - Corneal transplants are mostly successful (in the first year), but in the long run, it has side effects.
Matthew, Denise, Arthur, Hakeem, Norul
By group 3571114
1: Adult and embryonic stem cells are different because adult stem cells are already differentiated but embryonic stem cells are not yet and can be differentiated.
2: The limbal stem cells are taken from the healthy eye of the patient, if one exists, or a live donor--usually a sibling or a parennt. Less often, limbal stem cells are taken from a cadaver. An emerging approach uses a fraction of the amount of limbal stem cells normally taken from a live donor and grows them in the laboratory.
The stem cells are parent cells that give rise to the corneal epithelial cells.
3: Amniotic membrane is what surrounds the fetus in the womb. The amniotic membrane is used during cornea transplantation is because it can be used in 'wound healing' for many years. Amniotic membranes have large amounts of growth factors which are ideal for tissue regeneration.
4: Success of corneal transplant is about 85%. The 15% failure is due to glaucoma, retinal degeneration, or optic nerve disease.
5: It turns out that the success is slightly higher because of the state of the cornea using stem cells is better and less damaged than conventional transplantation.
Links
http://www.pslgroup.com/dg/1026F6.htm
http://www.stlukeseye.com/surgical/CornealTransplant.asp
http://www.rnib.org.uk/eyehealth/eyeconditions/conditionsac/Pages/corneal_transplantation.aspx
http://www.ncbi.nlm.nih.gov/pubmed/11896990http://www.theuniversityhospital.com/healthlink/archives/articles/limbalstem.html
http://www.peposevision.com/page.php?p=44
http://stemcells.nih.gov/info/basics/basics5.asp - a) Conclusion: Embryonic Stem Cells can become any kind of organ, while adult stem cell are restrained as they are already developed.
Epithelial of the cornea is maintained by stem cells. - http://www.stembook.org/node/588
Stem cells might not be able to be controlled properly. -(www.cordbloodbankupdates.com/what-are-some-concerns-with-stem-cell-use-in-cornea-transplants/ http://www.sciencecases.org/cornea/cornea3.asp)
25 - 75% success rate - http://www.nei.nih.gov/health/cornealdisease/#5
Amniotic membranes have been widely used for many years.They make an ideal matrix because they do not trigger an immune reaction in the recipient. -http://www.ucdmc.ucdavis.edu/news/corneapr.html)
Conclusion - A2. Lucy regained some sight....
By: Mitchel, Qi Ren, Roy, Jeremy and Pasakorn
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